Rust-proofing coating for iron and steel.



Nrrnn STATES WILLIAM H. ALLEN, or IJEI'noI'r, MICHIGAN,

RUST-.PEOOFING COATING F93. IRON AND STEEL.

To all whom itmay concern:

I Be it'known that 1, WILLIAM H Annnn, a

citizen of the United States, and residing at Detroit, in the county of Wayne and State ofMichigan, have invented a new and Improved Rust-Proofin Coating for llron and Steel, of which the ollowing is a specification.

This invention: relates to the protection of articles of iron and steel from rusting by producing surfaces of phosphates of iron,

basic in character, on said ar'ticles,' -and its object is to provide a rust-proofing liquid which can be applied by means of a brush,

air spray or by dipping; While the exactformula of the basic phosphate surface is" uncertain, it is thought to be 3FePO 3Fe Oj 10Fe (P0,)

This invention consists of a liquid which may beapplied in any desired manner to the articles to be treated, and in the co'ating of surfaces of iron and steel with this liquid, in contradistinction to the present, method of immersing the articles in' a rust-proofing '25 bath consisting of a. solutio'nfl acid phosphates wherein the articles, remaintuntll the. proper surface on these articles is obtained,

a bbilmg point.

' which case the liquid penetrates-between the scales and the metal and causes the (scales to fall ofl", v The coating liquid is prepared by mixing the acid. phosphates of iron,-w ith a (weak' solutionof phosphoric acid. While many acid phosphates are theoretically available, those of iron, zinc and manganese are alone f.

415 practical for anything but laboratory ex pemments. Where the phosphatesare norq Specification of Letters Patent. Application filed mums, 1917. Serial no. Iamao.

usually two hours when the bath is kept at To accomplish this invention, a'liquid consisting. of an acid solution of a phosphateof- Patented am. a, rare.

mally insoluble, suflicient' phosphoric acid is added to produce a superor acid-phosphatc that will remain in solution. To give body to, the liquid, an excess of acid phosphate may be added to the liquid, or a sili-' .cate or clay may beemployed. If desired,

the surfaces to be treated may be first heated, i

which insures a more intense action of the coating. The coating is lefton the article treated until chemical equilibrium has been established and may thereafter be brushed .ofi or left in place until it flakes ofl',

' The preferred composition of this coating ,/is one hundred'parts of an approximately ten per cent. solution of phosphoric acid in water, to which is added approximately one per cent. by weight of ferric phosphate,

which will usually so saturate the acid that it is incapable of uniting with. any more.

phosphoric acid, and" is also asaturatedso lution.

t'ecting thesurfacesof the steel work of buildings and bridges, before or after erec- This liquid isparticularly useful if orprotion, and of. railway "vehicles, especially freight cars.

I clai'mz- 1-. A- liquid surfaces-ofiron and stee consisting .of an approximately tenfper. cent. solution of nrg rust-'proofin .to be applied to phosphoric acid in water in which is dis;

solved" approximately 'oneF'per cent. by weight of ferric phosphate. 2; A liquid rust-proofing to be applied to surfaces of iron and steelconsistmg; of a" solution of phosphoric acid and ferric phosphate in water, together of inert-matter.

with a? thickening 

